Bull Micral 45 - revival

[fneck]

Today I filled the motherboard with 6 MB



At first I did not see the count until 6 MB. After a few tries I found that SW2-2 had an influence on the memory like this:

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SW2-1 SW2-2    Memory avaible
 OFF   OFF     limited to 2 MB
 ON    OFF     limited to 4 MB
 ON    ON      up to 6 MB

In fact, I think the rest of the memory must be available as EMS memory but as a driver that I do not have is required I can not test it.

[Lenord]

At first I did not see the count until 6 MB. After a few tries I found that SW2-2 had an influence on the memory like this:

Thanks you. So much memory, you're lucky)
This is what i get (only if last 2 slots are populated, otherwise all zeros)

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SW2-1 SW2-2  EMS SIZE
 OFF    OFF   0.5 MB
 OFF     ON     2 MB
  ON    OFF     0 MB
  ON     ON     0 MB
 

Have you tried my combination (1-OFF, 2-ON)?

I've also found photos of strange version of BM. This is called Bull Micral 45V and you have 45 model without any letters. I don't know, what's the difference. Photos of exterior and insides (nice battery solution ):

It has strange "Genpacific" v1.2R BIOS:


Unfortunately, that PC seems to be sold or recycled already.

[fneck]

Have you tried my combination (1-OFF, 2-ON)?

Yes, but I have difficulty making conclusions.
1- the boot display depends directly on the position of the jumpers but not on the saved configuration
2- the MEM command indicates the same thing as the boot
3- the EMT51 program returns the amount of memory saved by the configuration

For exemple, on this screen I have 5120 KB on the setup configuration, jumpers is SW1-1 OFF & SW1-2 ON :

[Lenord]

Yes, but I have difficulty making conclusions.
1- the boot display depends directly on the position of the jumpers but not on the saved configuration
2- the MEM command indicates the same thing as the boot
3- the EMT51 program returns the amount of memory saved by the configuration

Same for me.
And if boot display and config amount differs, EMT gives errors. Like on your photo.

For exemple, on this screen I have 5120 KB on the setup configuration, jumpers is SW1-1 OFF & SW1-2 ON :

I got same results when i tried to set 3MB via config with 0MB on boot.
I don't know why EMT is even able to detect that amount.

So what was displayed on boot in this position?
What changes if you install only 4x SIMMs in this switch configuration?

[Lesarthois]

I've also found photos of strange version of BM. This is called Bull Micral 45V and you have 45 model without any letters. I don't know, what's the difference. Photos of exterior and insides (nice battery solution ):

It has strange "Genpacific" v1.2R BIOS:


Unfortunately, that PC seems to be sold or recycled already.

Very strange indeed I don't know about the 45 V. Strangely, if I type "Micral 45" on Google, it offers to autocomplete it as "bull micral 45м" this small M being a cyrillic character. It doesn't get any result tho. My best guess, given the 1990 BIOS date, is that some company bough a stock of Micral 45 and adapted them for the Soviet-then-Russian market.
The V might have been added to signal an export version? From the picture, it looks added in factory, it's not just a sticker.

[Lenord]

[...]

I have an answer for "M" - that's because M and V share a key on RU/EN keyboard layout. So that's just a misprint for 45V.

Maybe that's an export version, I also think that V letter was original, not a sticker.
I couldn't find anything about GenPacific brand.
And v1.2r bios version might mean R(ussia).


I've found 3-4 traces of BM 45V in russian internet from 2011 to 2018.
But also that might be a single PC being resold by various junkmen.

And mine motherboard seems to be also some modification of Model 45, not 45V.
Because it has 8MHz CPU and Fabien said that my v2.0 bios sets his CPU to 8MHz on start, so it was intended.

[waltje]

Hi,

I contacted Fabien earlier this week, about the Micral 45. Basically, I am adding an emulation of it
to my PC systems emulator project (see http://www.varcem.com for info), and, as all of us, was
looking for information

The machine works, but is not complete yet.

1. I have found the meaning of the two switch blocks, and some others. See page 239 and on in
the book I posted here: http://waltje.varcem.com/book.pdf. That is literally the ONLY info
I could find on it...

2. I hope Lenord will be able to "map" the switches to the bits in the keyboard controller. The BIOS has to
be able to read them, and this usually happens through the keyboard controller's "input port" bits.

For now, my emulated M45 works with Lenord's V2.0 BIOS, but, for some reason, not with Fabien's

Regards,

Fred

[fneck]

Hi, welcome here Fred

Thank you for you precious help!
I copied below the corresponding page 239 :



I do not really understand the corresponding part for the memory. I'll have to re-try.

What information do you need to emulate with my BIOS?

[Lenord]

I have found the meaning of the two switch blocks, and some others. See page 239 and on in the book I posted here: http://waltje.varcem.com/book.pdf. That is literally the ONLY info I could find on it...

Thank you much, Fred! Best 2.000 page book I've ever read
Despite some of my research efforts were basically correct, I didn't even suppose these functions, they're almost impossible to guess.
As i've understood "OFF/ON" in that table shows default value, but i don't know what means "*"-symbol.

I've compared that with my schemes and rechecked the board. I have some corrections and questions.
Question mark means I am not sure which position (ON/OFF) does the specified action.

First, SW2:

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 #1 ON? = mouse enable
 #2 ON = give IRQ3 to mouse (IRQ5 in your manual is wrong)
 #3 ON = give IRQ5 to mouse (IRQ3 in your manual is wrong)
 #4 ON?? = enables CP8, Serial, Parallel (otherwise i don't understand this function)
 #5 ON = set SCSI address 328-32Fh, OFF = 328-32Fh
 #6 ON = give IRQ7 to SCSI
 #7 ON = give IRQ15 to SCSI
 #8 ON = give IRQ5 to Parallel port (=COM2)
 #9 ON = give IRQ7 to Parallel port (=COM2)
#10 ON = give IRQ3 to CP8 (=COM1) 

Seems that available serial port on this machine should be COM0 with fixed IRQ (4?), CP8 interface implemented via COM1 and COM2 is parallel port.
So theoretically, if one needs, he can continue reverse-engineering and get one more COM port from 20-pin CP8 interface.

Then, SW1. Howled in relief that half of switches ( #3, #6-8) does nothing. The rest are:

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 #1 = memory setup
 #2 = memory setup
 #4 ON = sets Mono mode for external (what else means addon?) ISA videocard
 #5 ON = enables external videocard

To conclude, this PC already has not so much switches but most of them are just to manage built-in devices.
Nothing close to any normal 286 PC, no hardware turbo key and strange memory setup.
This is my latest version of switch setup.

I hope Lenord will be able to "map" the switches to the bits in the keyboard controller. The BIOS has to
be able to read them, and this usually happens through the keyboard controller's "input port" bits.

For now, my emulated M45 works with Lenord's V2.0 BIOS, but, for some reason, not with Fabien's

I've found three - J1 jumper (32-pin, port 15), switch SW1 #4 (33-pin, port 16) and Turbo LED (24-pin, port 23).
Other switches aren't connected with keyboard controller directly. I will try to find something else but it's almost impossible because they may come through lots of logics, some of which is pre-programmed. I've tried that for SW2, maybe that helps.

It's hard to be emulated because we even don't have any datasheet for its chipset(
I can't imagine how you got that working, but that's great!

I do not really understand the corresponding part for the memory. I'll have to re-try.

Me too. First two settings do compare with my results.
Third setting isn't clear, but something connected with second bank.
Fourth setting (=mine) means nothing useful and there must be misprint (double OFF OFF)

I hope now you could check that.
Please try with 2x, 4x and 6x 1Mb simms in slots and fill-in 3x tables in the same order.

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EMS size: #1   #2
     ?Mb  ON   OFF
     ?Mb  OFF  OFF
     ?Mb  ON   ON
     ?Mb  OFF  ON

I will do the same but I am not sure that my board works correctly.

Also if you have Inport mouse(or at least COM with DB25 adapter), you could check if this mouse stops working when you change #1 or #4 in SW2 block. I don't know, but there should be any DOS software which can be used to test mouse.

I came to an idea, that my board is ok but was cropped to 8MHz and 2Mb RAM by manufacturer.
I think, that our boards have different pre-programmed logics, especially Z322 which is not soldered thus replaceable.
I've restored clock scheme from the CPU:

You see, that Z322 controls both memory switches and clock generation. I couldn't find chipset's datasheet but anyway, this could be the reason.
So I need more photos of some parts of your board to ensure. I have to check the labels of the chips, so i need closer look.
I've marked them with red rectangles.

[fneck]

I did some tests with different combinations of memories and switches.

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	SW1	Display		Memory
		at boot		in Ms-Dos
		
2x1MB	0/0	640+1024	2048
	1/0	640+1024	2048
	1/1	640+1024	2048
	0/1	640+1024	2048
	
4x1MB	0/0	640+1024	2048
	1/0	640+3072	4096
	1/1	640+3072	4096
	0/1	640+1024	2048
	
6x1MB	0/0	640+1024	2048
	1/0	640+3072	4096
	1/1	640+5120	6144
	0/1	640+1024	2048

[fneck]

I tried to do the same test with 256KB memories but it does not work. I don't know if this is a memory Simms problem or if my computer does not accept them.

[Lenord]

I did some tests with different combinations of memories and switches.

Thank you very much! That stuff becomes little more determined with your help.
I've done the same and created better form of both results:

According to what you've got, turning ON #1 gives 4Mb and together with #2 allows 6Mb of memory (total).
But on my PC these 1/0 and 1/1 settings don't give any EMS and the remaining settings don't work (ERR=parity error during DOS boot) with less than 6x SIMMs. I can just choose between 512k and 2048k EMS and this is completely different from your 1024K, 3072K, 5120K range.

I can just say, that if we compare that with manual,

Those settings are closer to my results than to yours. I can't explain this.

I have a little progress in other area. I got 12MHz and turbo on.



To do that, I had to ground P23-port of KBC and hold grounded for a while (~2.5s) to keep it like this later on. The trick works only at bootup, later it doesn't hold, just turns on the LED.
SPEED /+ or SPEED /- command both reset that (if you aren't holding it grounded manually).

There is rather complicated way to turn turbo later. This works if you run any SPEED ... command and ground P23 at the same time. Then it holds.

I've made extra measurements and updated my CLK scheme:

On this pic, green means that I've discovered digital data flow there.
When turbo is OFF (3-not grounded), then 21, 18 pins are just static. When it's turned on, these lines start exchanging with some data.

I am not sure, but maybe your BIOS with 12MHz on startup will help.
If not, that means that firmware in our keyboard controllers differs too and I have rare BM45 variation with cropped capabilities.

And concerning other settings. By default, mouse is turned off, same for parallel port but unused CP8 takes IRQ.
If you have an inport mouse, please check if it's working with SW2 #1-OFF.
If you have just com mouse and DB9-DB25 adapter, check if that works with SW2 #1-OFF and SW2 #3-OFF.
I think that these settings will disable inport mouse but allow COM mouse.

Also i need some photos, mentioned earlier.

[fneck]

OK, I'll do the test with mices soon, but I'm not sure I have a import mouse, and also for the photos.

[Lenord]

Ok.
Strange that yours don't work with 256K SIMMs. Both 256K and 1M were standard SIMM sizes for 286s.
I've also discovered that it won't work with 4Mb SIMMs, but that was rather obvious.

[fneck]

Great news this evening. The contact we had by email found the BM45's documentation





The other pages I received are in the ZIP file :
https://system-cfg.com/files/BM45_doc_(extrait).zip

But even with the doc I did not understand exactly how SW1-1 and SW1-2 worked.

I came to an idea, that my board is ok but was cropped to 8MHz and 2Mb RAM by manufacturer.
I think, that our boards have different pre-programmed logics, especially Z322 which is not soldered thus replaceable.

It seems that you are right about Z322 and memory capacities.

A very big thank you to the one who did this research. I'm going to propose to him to join us here